Breast cancer is one of the biggest public health problems in the world. It is the leading cause of morbidity and mortality and the most common form of invasive cancer in women in both developed countries and developing countries. Colombia is no exception. Mutations in the BRCA1 and BRCA2 (BRCA) genes are the primary causes of the development of hereditary breast and/or ovarian cancer. These diseases require the implementation of early diagnosis techniques for successful treatment. Patients that carry the BRCA gene mutation have up to a 90% risk of developing one of these diseases over their lifetime, with a significantly increased likelihood of contracting the disease at younger ages and with severer clinical symptoms. Identifying patients that carry mutations in these genes is key to developing appropriate strategies for genetic counselling, population screening, prevention and treatment. Up to now, in daily clinical practice the molecular analysis of BRCA genes has been implemented as a fundamental tool for management and prevention in women with a family history of breast and ovarian cancer. Unfortunately, Colombia does not have a population registry to provide us with data on the frequency and spectrum of mutations in BRCA genes circulating in the country. For this reason, the design and implementation of a well-structured registry system for BRCA1 and BRCA2 gene mutations in patients with breast cancer and/or ovarian cancer is needed in order to develop effective early detection, prevention and treatment programs, which will enable us to make a significant impact on the rates of incidence, mortality and disease-free survival for both of these pathologies in Colombia.

Despite the evidence that supports the value of BRCA1/2 genetic counselling and testing for managing hereditary breast and ovarian cancer risk these two tools are underutilized among black women. Socio-cultural barriers related to poverty (e.g., limited or no access to services) and culture (e.g., shared attitudes/beliefs) are potential explanations of racial disparities. Compared to whites, young black women are disproportionately afflicted with breast cancer, a proportion of which may be due to BRCA1 or BRCA2 mutations, they are more likely to be diagnosed with breast cancer at a younger age and to die from this disease. Furthermore, the prevalence of BRCA1/2 mutations in black women ranges from 12% to 21% (Gao et al. 2000), making the benefits of genetic counselling and testing to this group clear and compelling. Interventions and resources are needed to ensure that the benefits of the BRCA1/2 discovery are extended to all women with increased risk of carrying these mutations.

Most BRCA1/2 mutations are rare and many have been reported only in single families. However, few recurrent mutations with founder effects have been found in European, American, Asian and Hispanic populations. The frequency and spectrum of BRCA1/2 germ line mutations has been shown considerable variation by geographic region and ethnic group. Most genetic epidemiological studies of the BRCA genes have been performed among Caucasian populations, with the exception of a few studies involving other ethnic groups, such as Asians, African Americans and Hispanics. It is of increasing importance to identify women who carry mutations in breast cancer susceptibility genes because preventive strategies may be applied. At present, genetic testing is offered in many centers throughout North America and much of Europe, Australia and Israel, but is not commonly available in South America. Torres and colleagues have identified three common founder mutations in BRCA1 and BRCA2 in Colombian breast/ovarian cancer families that account for 80% of all BRCA1/2 mutations identified in this cohort. These mutations are specific for this Hispanic population as they absent in Hispanic cancer families of mainly Mexican descent from South California. The proportion of all mutations that are founder mutations in a population has important implications for the mutation detection strategies that are used to detect mutations, at both the research and the clinical testing level. In populations with a high percentage of founder mutations such as the Ashkenazi Jewish population, the Polish population and now the Colombian population a mutation-specific screening or a targeted rather than a full screening approach is possible. It is the goal of this study to assess breast cancer risks associated with germ line mutations in the BRCA1 and BRCA2 genes in the Colombian population. In particular, the prevalence and penetrance of the three common Colombian founder mutations will be investigated.